Cloud Atlas by David Mitchell is as ambitious as it is entertaining, reaching back through colonial times to a bleak distant future and back again.

BBC News Online is reviewing one of the shortlisted books each day, leading up to the Booker announcement on Tuesday, 19 October.

David Mitchell has taken six wildly different stories, set in different times, and melded them into one fantastic and complex work.

That it works at all is a surprise, that it is so brilliantly engaging shows what a talent for storytelling the author has.

Cloud Atlas begins in the mid-19th Century, told through the diary of traveller Adam Ewing who visits the Chatham Isles, near New Zealand.

The islands have seen violent bloody times, with peaceful, yet "uncivilized", natives brought under slavery by the more "civilized" invaders, while the colonialists sit by and do nothing.

But the reader cannot get too comfortable as the narrator is cut off mid-story to embark on someone else's tales.

Taut anticipation

This time we have the life of flamboyant composer Robert Frobisher, a cad escaping to find fame and fortune in Belgium in the 1930s.

In his letters to his lover back home he tells of worming his way in with a famous but ailing Belgium composer, helping himself to whatever he fancies, including his wife.

But his letters are cut short, leaving the reader begging to know what happens next.

Cloud Atlas marches through six stories apace, leaving clues as to how the stories can possibly be linked, with some more tenuous than others.

Several of the stories are set in living memory - a political thriller set in the 1970s and a modern day story of a publisher incarcerated in an old people's home at the age of 65.

Cloud Atlas then spins off into a future led by corporations, producing oppressed genetically modified humans to carry out the less attractive jobs, with no need to experience such things as pleasure or contentment.

Moral message

The story of Sonmi 451, a server in a fast food diner, knits in the themes of greed and oppression first brought up in the diary of Adam Ewing.

The final tale shows what could happen if greed and corruption is allowed to take over, ending in a big bang scenario.

A homage to other great writers can be seen in this fascinating book, from Orwell and Huxley to Matthew Kneale and Carl Hiaasen but with an imagination and storytelling ability unique to Mitchell.

The structure of the book is a challenge, with the first story only completed at the end of the book, while the second is the penultimate to be completed, and so on.

It can be jarring to be stopped mid-narrative to start on another story, told in a completely different style, in a language to which the reader needs time to adjust.

It is also a long, complex book which requires racing through to remember who has been doing what.

There is a preachy message to be found in Cloud Atlas but just as much as you will good to prevail in some stories you are firmly on the side of the raffish characters, willing them to triumph.